In the lens-interchangeable digital camera, as the interchangeable lens unit to be attached to the camera body unit has lens characteristics peculiar to each lens unit, lens characteristic data of the interchangeable lens unit is transmitted to the camera body unit in advance when using the interchangeable lens unit. In the camera body unit, the transmitted lens characteristic data of the interchangeable lens unit is used as correction data when image processing is performed to an image signal taken in an imaging unit. Accordingly, it is difficult to allow the camera to take an image until the transmission of all lens characteristic data of the interchangeable lens unit is completed at the time of activating the camera and other occasions, therefore, a great photo opportunity coming just after the change of the interchangeable lens unit may be missed.
In response to the above, a technique is known (for example, refer to JP-A-2010-237515 (Patent Document 1)), in which lens characteristic data transmitted once is stored with a lens identifier and the lens characteristic data is not retransmitted when the interchangeable lens unit having the same identifier is attached. Accordingly, in the case where the changed interchangeable lens unit has been used before, transmission of lens characteristic data performed just after the change can be omitted, therefore, it is possible to shorten a period of time until the camera is ready to take an image and it is possible to take an image just after changing the lens.